The use of lubricating strips in wet shaving systems is generally well known. Such lubricating strips typically exude lubricants, such as polyethylene oxide, from a plastic matrix that normally remains intact throughout the operational life of the razor. See, for example, U.S. Pat. Nos. 5,454,164, 4,872263, and 4,170,821, the disclosures of which are incorporated herein by reference in their entirety. The lubricant exuded from the plastic matrix allows the razor blade to glide with greater ease along the surface of the skin of the user thereof, thereby reducing the resistance, i.e., drag, of the razor on the skin. The amount of polyethylene oxide lubricant that exudes from the matrix is generally a function of, inter alia, the permeability of the release matrix and the specific diffusion properties of the polyethylene oxide lubricant. Consequently, the amount of polyethylene oxide available at the surface of the polymer matrix for application to the razor blade gradually decreases over the operational lifetime of the lubricating strip. Furthermore, hydrogel lubricating strips, which swell in the presence of water thereby forming channels through which the lubricant diffuses to the surface of the strip, are also known. See, for example, U.S. Pat. Nos. 5,626,154 and 4,875,287, the disclosures of which are incorporated herein by reference in their entirety. By virtue of the swelling of the hydrogel material, the diffusion process is augmented, however, the amount of lubricant arriving at the surface of the strip, although fairly consistent at the beginning of use, is still limited by diffusion characteristics, and the amount of lubricant available once again decreases slowly over time.
The instant invention provides a lubricating strip comprising a biodegradable polymer, preferably a surface-eroding non bulk-eroding biodegradable polymer, for the delivery of polyethylene oxide, or any other lubricant, additive, or adjuvant useful in wet shaving systems. Because the polymer comprising the lubricating strip gradually erodes at a controlled rate with each razor stroke, the lubricating strip comprising such biodegradable polymer, or such preferred surface-eroding, non bulk-eroding biodegradable polymer, provides a fresh consistent amount of lubricant to the skin of the user throughout the operational life of the razor.